Biomedical subjects

Thinus F Kruger

Publications and source records attributed to Thinus F Kruger.

8 recordsLinked to original sources

PubMed2006

Is the addition of metformin efficacious in the treatment of clomiphene citrate-resistant patients with polycystic ovary syndrome? A structured literature review.

OBJECTIVE: The aim of this literature search is to establish if metformin is efficacious when given to clomiphene citrate (CC)-resistant polycystic ovary syndrome (PCOS) patients. DESIGN: Medline database was searched from 1 January 1980 to 1 January 2005. Inclusion criteria were prospective randomized control trials where metformin was randomized either with placebo or CC to induce ovulation in the CC-resistant patient. RESULT(S): Group 1: Four trials were prospective double-blind placebo controlled. When the data of the four trials were pooled, the overall effect of the addition of metformin in the CC patient was P=.0006 with a 95% confidence interval (CI) of odds ratio (OR) 1.81-8.84. Group 2: In two trials the randomization was only prospective. When the data of these two trials were pooled, the overall effect of the addition of metformin in the CC-resistant patient was P<.0001 with a 95% CI of OR 6.24-70.27. Groups 1 and 2: The combined data show an overall effect of P<.0001 with a 95% CI of OR 3.59-12.96. CONCLUSION(S): The addition of metformin in the CC-resistant patient is highly effective in achieving ovulation induction.

Clomiphene↗

PubMed2005

Endotoxic shock after gamete intrafallopian transfer.

OBJECTIVE: To report an extremely rare case of endotoxic shock due to Enterobacter cloacae that occurred after laparoscopy for gamete intrafallopian transfer (GIFT) in a nulligravid woman. DESIGN: Private fertility center in Cape Town, South Africa. SETTING: Case report. PATIENT(S): A 34-year-old woman with primary infertility. INTERVENTION(S): Routine preparation for GIFT procedure, sonar aspiration to obtain oocytes, followed by GIFT. Endotoxic shock developed within hours after the procedure, followed by admission to the intensive care unit, intravenous antibiotic therapy, mechanical ventilation, and abdominal hysterectomy. MAIN OUTCOME MEASURE(S): Preventing patient mortality and morbidity. RESULT(S): Discharge from the intensive care unit occurred on day 11 after GIFT, which was day 8 after surgery. A MEDLINE search (1980 to 2003) found no previous literature on endotoxic shock associated with assisted reproduction. CONCLUSION(S): Gram-negative infection with subsequent endotoxic shock after assisted reproductive techniques is extremely rare. As this case report shows, early diagnosis and active management of these cases are mandatory to prevent serious complications and mortality.

Adult↗

PubMed2005

Effect of reactive oxygen species produced by spermatozoa and leukocytes on sperm functions in non-leukocytospermic patients.

OBJECTIVE: To investigate whether there is an impact of different sources of reactive oxygen species (ROS) on sperm functions. DESIGN: Prospective study. SETTING: Patients at the Center for Dermatology and Andrology, Giessen, Germany. PATIENT(S): Semen collected from 63 randomly collected patients attending the IVF unit of the University of Giessen, Germany. INTERVENTION(S): Only patients with nonleukocytospermia were included in this study. MAIN OUTCOME MEASURE(S): Sperm count and motility before and after sperm separation by swim-up, morphology, DNA fragmentation, and extrinsic (by leukocytes) and intrinsic ROS production (by spermatozoa) were evaluated. RESULT(S): Leukocytes correlated significantly with extrinsic ROS production (r = 0.576), but markedly less with intrinsic ROS production (r = 0.296). Sperm count, morphology, and motility in the ejaculate were markedly more affected by extrinsic than by intrinsic ROS. The DNA fragmentation was strongly positively correlated with intrinsic ROS production, whereas this correlation was weaker for extrinsic ROS production. No correlation was found between DNA fragmentation and the number of leukocytes, whereas the correlations with motility in the ejaculate and the motile sperm count after swim-up were highly significant. Moreover, significant differences were observed for extrinsic and intrinsic ROS production between groups of patients having a high (> or = 1 x 10(6)/mL) and a low number (<1 x 10(6)/mL) of leukocytes in the ejaculate. CONCLUSION(S): The origin of ROS seems to have an influence on the site of the damage. Because leukocyte counts <1 x 10(6)/mL caused a significant decrease of motility and DNA integrity, the threshold given by the World Health Organization (WHO) should be re-evaluated.

Adult↗

PubMed2005

Use of a zona laser treatment system in assisted hatching: optimal laser utilization parameters.

OBJECTIVE: This study aimed to establish the benefit of laser micromanipulation of the zona pellucida as a method of assisted hatching and to determine the optimal technical settings. DESIGN: Prospective pilot study. SETTING: University teaching hospital. ANIMAL(S): Six- to 8-week-old F1 female mice. INTERVENTION(S): Mouse embryos were treated with a laser (Hamilton Thorne Research) using both research and preset clinical settings. The research option allows the user to alter pulse duration, number of pulses, and beam intensity. In this study, laser intensity and duration, as well as the depth and number of disruptions, were altered. MAIN OUTCOME MEASURE(S): Embryos were scored after treatment as either arrested blastocysts, arrested during hatching, hatched, or degenerate. RESULT(S): The treatment where the laser intensity was halved but the number of laser pulses used was doubled was the most beneficial treatment. Zona thinning was not effective. CONCLUSION(S): The study showed that laser-assisted hatching can safely and significantly increase the percentage of embryos reaching the hatched blastocyst stage. A proportionately sized hole in a human embryo may have the same beneficial effect as has been shown in this study.

Animals↗

PubMed2004

Influence of deoxyribonucleic acid damage on fertilization and pregnancy.

OBJECTIVE: To investigate sperm DNA damage in relation to fertilization and pregnancy. DESIGN: Prospective study. SETTING: The Institute of Reproductive Medicine, Giessen, Germany. PATIENT(S): Semen collected from 249 patients attending the IVF program. MAIN OUTCOME MEASURE(S): The percentage of terminal deoxynucleotidyl transferase-mediated dUDP nick-end labeling- (TUNEL-), Fas-, and annexin-V-positive sperm and the proportion of green-fluorescing sperm in the acridine orange stain was determined and correlated with sperm concentration, motility, fertilization, and pregnancy. RESULT(S): Significant correlations with the concentration of motile sperm were only found for the acridine orange stain (before and after sperm separation) and for the TUNEL assay (after sperm separation). Moreover, patients whose sperm had a high percentage of DNA fragmentations showed significantly lower pregnancy rates (TUNEL assay: 19.05% vs. 34.65%; acridine orange stain: 24.58% vs. 37.93%). The apoptosis parameters (annexin V binding and Fas expression) showed no statistically significant differences. CONCLUSIONS: Our data clearly demonstrate that DNA fragmentation, as determined by the TUNEL assay, is predictive for pregnancy in IVF. This implies that spermatozoa with DNA fragmentation can still fertilize an oocyte but that when paternal genes are "switched on," further embryonic development stops, resulting in failed pregnancy. It seems that, at least in the patients we analyzed, apoptosis in the sperm does not play a role for fertilization. This would imply that DNA fragmentation in human spermatozoa is caused by external factors, such as reactive oxygen species, rather than by apoptosis.

Acridine Orange↗

PubMed2003

Relationship between zona pellucida-induced acrosome reaction, sperm morphology, sperm-zona pellucida binding, and in vitro fertilization.

OBJECTIVE: To evaluate the possible relationships between sperm morphology, acrosome responsiveness to solubilized human zona pellucida, and sperm-zona binding potential among [1] consecutive andrology referrals and [2] randomly selected in vitro fertilization (IVF) cases. DESIGN: Prospective analytical study. SETTING: Academic training hospital.Randomly selected couples consulting for infertility. INTERVENTION(S): Acrosome reaction response to solubilized human zona pellucida was recorded. MAIN OUTCOME MEASURE(S): We determined the difference in the percentage of sperm that acrosome reacted after exposure to solubilized zona pellucida and spontaneous acrosome reaction. The results were expressed as percentage zona induced acrosome reaction (ZIAR). RESULT(S): Data were analyzed using correlation coefficients (r) and receiver operator characteristics (ROC curve analyses). The ROC curve analyses indicated ZIAR to be a sensitive indicator for fertilization failure during IVF therapy, with sensitivity and specificity of 81% and 75%, respectively. For andrology referrals, a positive and statistically significant correlation existed between ZIAR data and sperm morphology (r = 0.65) and sperm-zona binding (r = 0.57). CONCLUSION(S): ZIAR results provide further information regarding dysfunctional sperm and can be used as an additional diagnostic test. Our results predicted fertilization failure during IVF treatment.

Acrosome Reaction↗

PubMed2003

Monitoring technologist reading skills in a sperm morphology quality control program.

OBJECTIVE: The value of sperm morphology as a predictor of a man's fertilizing potential has often been challenged because of different classification systems used to distinguish between normal and abnormal spermatozoa. The study aimed to monitor the reading skills of 53 laboratory technologists who are enrolled in a continuous quality control program for sperm morphology assessment. DESIGN: Prospective analytical study. SETTINGS: Academic hospital and academic institution setting. PATIENT(S): Sperm samples from the sperm donor program and andrology technicians from sub-Saharan Africa. INTERVENTION(S): Papanicolaou-stained sperm slides were prepared and shipped on a quarterly basis to participating laboratories. Papanicolaou-prestained sperm morphology slides were used as test material for 21 months. MAIN OUTCOME MEASURE(S): Percentage normal spermatozoa.A new statistical model was developed to record reading skills of the participating technicians. Reading skills were classified as marginal (5.7% of cases), good (11.3% of cases), and excellent (83% of cases). RESULT(S): Participants maintained their morphological reading skills and agreed with the reference laboratory by not exceeding a SD limit of 0.2 to set stringent standards for the program. CONCLUSION(S): Technician proficiency can be monitored using the results of a quality control program. A continuous quality control program can be initiated only after intensive training, because baseline values at the onset of the quality control program serves as an internal reference value.

Clinical Competence↗

PubMedDate not supplied

DNA fragmentation of spermatozoa and assisted reproduction technology.

Despite the ever-increasing knowledge of the fertilization process, there is still a need for better understanding of the causes of sperm DNA fragmentation and its impact on fertilization and pregnancy. For this reason, human sperm DNA fragmentation was investigated by means of the terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) assay and the production of reactive oxygen species (ROS) in the ejaculate and in the spermatozoa themselves. These data were correlated with fertilization and pregnancy data from IVF and intracytoplasmic sperm injection (ICSI) patients. Sperm DNA fragmentation did not correlate with fertilization rate, but there was a significantly reduced pregnancy rate in IVF patients inseminated with TUNEL-positive spermatozoa. ICSI patients exhibited the same tendency. This implies that spermatozoa with damaged DNA are able to fertilize an oocyte, but at the time the paternal genome is switched on, further development stops. The determination of ROS in the ejaculate and the percentage of ROS-producing spermatozoa revealed markedly stronger correlations between sperm functions (i.e. motility) and the percentage of ROS-producing spermatozoa. The influence of seminal leukocytes, known to produce large amounts of oxidants, on sperm DNA fragmentation should not be neglected.

DNA Damage↗